Katana by 'Geishu Yamagata Ihara Masamitsu and Shinsei Kotetsu Omote Kore Tsukuru' .

The present sword was entered into the 2008 NTHK shinsa held in the UK. According to the rejection slip, which stated that the sword was gimei, the panel assessed that the sword was the work of the Tadayoshi school of Hizen province and circa 1860. This is an interesting assessment and quite understandable if the hamon and construction of the blade are the sole considerations, as the sword, in the same manner as that quoted above, certainly looks like good Hizen work at the first glance. However, it is possible that this judgement is something of an oversimplification and has not fully considered the idiosyncrasies and characteristics of this provincial swordsmith. It is also difficult to see why, if it were actually made by a member of the Tadayoshi school, it has been effectively downgraded and signed by a smith that is less highly rated, the opposite of what might be expected.

Several other details of the present blade require consideration. I have never seen a nakago on a mainline Hizen-to with kesho yasurime, as shown on this sword, even in shinshinto times. Also the suguha hamon on Tadayoshi school blades always ends directly above the ha-machi rather than running past it (this could be changed by the machi-okuri of course) and the jihada is not fine enough to be termed Hizen konuka-hada. Lastly, and most convincingly, it seems that Masamitsu was known to make blades in the suguha style of Tadayoshi in at least this current sword and the one mentioned above from the Tempo period, which gained Tokubetsu Hozon. The relatively wide mihaba and the extended chu-kissaki are reminiscent of the sugata of the Keicho-shinto period and may indicate a conservative taste in sword-making. The reason for the similarity to Hizen-to may lie in the sword-making history of the province.

It seems that certainly in the early Shinto period at least, there was considerable movement of swordsmiths, between Hizen and Aki no Kuni. This included the mainline smith, shodai Yukihiro (grandson of shodai Tadayoshi) as well as other talented sideline smiths, more than one being retained by the ruling Asano clan in Aki no Kuni. In all I could find seven swordsmiths recorded who all went to Aki province from Hizen, mostly in the Kanbun era, circa 1661 (see Appendix for details). I think it perfectly possible that there were laterunrecorded generations who maintained Hizen’s influence over swords made in Aki and ifnot it may be that these seven laid the foundation of sword making in the province during the Shinto period, that was maintained into the Bakamatsu era. 

Hawley’s shows altogether three others named Masamitsu from Geishu, as follows:

MAS 480 Whose signature Oite Settsu Geishu Masamitsu indicates he was working in Osaka with a working date of 1716, earlier than the smith under discussion.

MAS 481 Who had the title of Izumo Daijo and is given a working date of 1830-44
MAS 482 Whose signature is the same as the sword being discussed here and whose active dates are given as 1859-71.

As we have seen that a Masamitsu was still productive at the age of 65, it would seem quite possible that the last two listed are the same man and the first is too early for consideration. It would also seem possible that, in accordance with the prevailing custom of the time, Masamitsu may have resigned his title as it does not seem to appear in the mei of these later works. However, there is no firm evidence, except the similarity of the calligraphy, to support this theory and so it must remain conjecture.